✨ Added helper functions to handle null reference warnings

README.md

@@ -24,7 +24,7 @@ services.AddDefaultSitemapServices<HttpContextBaseUrlProvider>();
 [HttpGet]
 public IActionResult Sitemap()
 {
-    var nodes = new List<SitemapNode> { new ("page.html"), new (Url.Action("Index")) };
+    var nodes = new List<SitemapNode> { new ("page.html"), SitemapNode.Create(Url.Action("Index")) };
     var sitemap = new Sitemap(nodes);
     return new SitemapResult(sitemap);
 }
@@ -36,8 +36,17 @@ public IActionResult Sitemap()
 public IActionResult SitemapIndex()
 {
     var sitemapIndex = new SitemapIndex();
+
+    // basic usage:
     sitemapIndex.Add(new SitemapIndexNode(Url.Action("Sitemap1")));
-    sitemapIndex.Add(new SitemapIndexNode(Url.Action("Sitemap2")));
+
+    // or: this extension function fixes the null reference warning
+    // on the line above:
+    var addResult = sitemapIndex.TryAdd(Url.Action("Sitemap2"));
+
+    // or: use the Create function
+    sitemapIndex.Add(SitemapIndexNode.Create(Url.Action("Sitemap1")));
+
     return new SitemapResult(sitemapIndex);
 }
 

src/Sidio.Sitemap.AspNetCore.Examples.MvcWebApplication/Controllers/SitemapController.cs

@@ -10,10 +10,10 @@ public sealed class SitemapController : Controller
     public IActionResult SitemapIndex()
     {
         var sitemapIndex = new SitemapIndex();
-        sitemapIndex.Add(new SitemapIndexNode(Url.Action("SitemapHome")));
-        sitemapIndex.Add(new SitemapIndexNode(Url.Action("SitemapNews")));
-        sitemapIndex.Add(new SitemapIndexNode(Url.Action("SitemapImages")));
-        sitemapIndex.Add(new SitemapIndexNode(Url.Action("SitemapVideos")));
+        _ = sitemapIndex.TryAdd(Url.Action("SitemapHome"));
+        _ = sitemapIndex.TryAdd(Url.Action("SitemapNews"));
+        _ = sitemapIndex.TryAdd(Url.Action("SitemapImages"));
+        _ = sitemapIndex.TryAdd(Url.Action("SitemapVideos"));
 
         return new SitemapResult(sitemapIndex);
     }
@@ -22,8 +22,10 @@ public IActionResult SitemapIndex()
     public IActionResult SitemapHome()
     {
         var sitemap = new Core.Sitemap();
-        sitemap.Add(new SitemapNode(Url.Action("Index", "Home")));
-        sitemap.Add(new SitemapNode(Url.Action("Privacy", "Home")));
+
+        // handle null warnings by using the TryAdd function
+        _ = sitemap.TryAdd(Url.Action("Index", "Home"));
+        _ = sitemap.TryAdd(Url.Action("Privacy", "Home"));
 
         return new SitemapResult(sitemap);
     }
@@ -32,7 +34,13 @@ public IActionResult SitemapHome()
     public IActionResult SitemapNews()
     {
         var sitemap = new Core.Sitemap();
-        sitemap.Add(new SitemapNewsNode(Url.Action("Article1", "News"), "Article1", "John Doe", "EN", DateTime.UtcNow));
+
+        // handle null warnings by checking the URL for null
+        var url = Url.Action("Article1", "News");
+        if (url != null)
+        {
+            sitemap.Add(new SitemapNewsNode(url, "Article1", "John Doe", "EN", DateTime.UtcNow));
+        }
 
         return new SitemapResult(sitemap);
     }
@@ -43,7 +51,9 @@ public IActionResult SitemapImages()
         var imageLocation = new ImageLocation("non-existing-image.jpg");
 
         var sitemap = new Core.Sitemap();
-        sitemap.Add(new SitemapImageNode(Url.Action("Index", "Home"), imageLocation));
+
+        // handle null warnings by using the Create function
+        sitemap.Add(SitemapImageNode.Create(Url.Action("Index", "Home"), imageLocation));
 
         return new SitemapResult(sitemap);
     }
@@ -54,7 +64,7 @@ public IActionResult SitemapVideos()
         var video = new VideoContent("non-existing-video-thumbnail.jpg", "Video1", "Video1 description", "non-existing-video.mp4", null);
 
         var sitemap = new Core.Sitemap();
-        sitemap.Add(new SitemapVideoNode(Url.Action("Index", "Home"), video));
+        sitemap.Add(SitemapVideoNode.Create(Url.Action("Index", "Home"), video));
 
         return new SitemapResult(sitemap);
     }

src/Sidio.Sitemap.AspNetCore.Tests/SitemapExtensionsTests.cs

@@ -0,0 +1,63 @@
+namespace Sidio.Sitemap.AspNetCore.Tests;
+
+public sealed class SitemapExtensionsTests
+{
+    [Fact]
+    public void TryAdd_WhenUrlIsValid_SitemapNodeAdded()
+    {
+        // arrange
+        var sitemap = new Core.Sitemap();
+        const string Url = "/index.html";
+
+        // act
+        var result = sitemap.TryAdd(Url);
+
+        // assert
+        result.Should().BeTrue();
+        sitemap.Nodes.Count.Should().Be(1);
+    }
+
+    [Fact]
+    public void TryAdd_WhenUrlIsEmpty_SitemapNodeNotAdded()
+    {
+        // arrange
+        var sitemap = new Core.Sitemap();
+
+        // act
+        var result = sitemap.TryAdd(string.Empty);
+
+        // assert
+        result.Should().BeFalse();
+        sitemap.Nodes.Should().BeEmpty();
+    }
+
+    [Fact]
+    public void TryAdd_WhenUrlsAreValid_SitemapNodesAdded()
+    {
+        // arrange
+        var sitemap = new Core.Sitemap();
+        const string Url = "/index.html";
+
+        // act
+        var result = sitemap.TryAdd(Url, Url, Url);
+
+        // assert
+        result.Should().Be(3);
+        sitemap.Nodes.Count.Should().Be(3);
+    }
+
+    [Fact]
+    public void TryAdd_WhenSomeUrlsAreEmpty_SitemapNodeAdded()
+    {
+        // arrange
+        var sitemap = new Core.Sitemap();
+        const string Url = "/index.html";
+
+        // act
+        var result = sitemap.TryAdd(Url, string.Empty, Url, " ");
+
+        // assert
+        result.Should().Be(2);
+        sitemap.Nodes.Count.Should().Be(2);
+    }
+}

src/Sidio.Sitemap.AspNetCore.Tests/SitemapIndexExtensionsTests.cs

@@ -0,0 +1,35 @@
+using Sidio.Sitemap.Core;
+
+namespace Sidio.Sitemap.AspNetCore.Tests;
+
+public sealed class SitemapIndexExtensionsTests
+{
+    [Fact]
+    public void TryAdd_WhenUrlIsValid_SitemapIndexNodeAdded()
+    {
+        // arrange
+        var sitemapIndex = new SitemapIndex();
+        const string Url = "/index.html";
+
+        // act
+        var result = sitemapIndex.TryAdd(Url);
+
+        // assert
+        result.Should().BeTrue();
+        sitemapIndex.Nodes.Count.Should().Be(1);
+    }
+
+    [Fact]
+    public void TryAdd_WhenUrlIsEmpty_SitemapIndexNodeNotAdded()
+    {
+        // arrange
+        var sitemapIndex = new SitemapIndex();
+
+        // act
+        var result = sitemapIndex.TryAdd(string.Empty);
+
+        // assert
+        result.Should().BeFalse();
+        sitemapIndex.Nodes.Should().BeEmpty();
+    }
+}

src/Sidio.Sitemap.AspNetCore/Services/ControllerSitemapService.cs

@@ -88,19 +88,28 @@ public IReadOnlySet<SitemapNode> CreateSitemap(Type controllerType)
 
     private HttpContext HttpContext => _httpContextAccessor.HttpContext ?? throw new InvalidOperationException("HttpContext is null");
 
-    private SitemapNode CreateNode(ControllerActionDescriptor action)
+    private SitemapNode? CreateNode(ControllerActionDescriptor action)
     {
         var url = _linkGenerator.GetUriByAction(HttpContext, action.ActionName, action.ControllerName);
 
-        if (_logger.IsEnabled(LogLevel.Trace))
+        if (_logger.IsEnabled(LogLevel.Warning) && string.IsNullOrWhiteSpace(url))
+        {
+            _logger.LogWarning(
+                "Unable to create sitemap URL for action `{Action}` in controller `{Controller}`",
+                action.ActionName,
+                action.ControllerName);
+        }
+
+        if (_logger.IsEnabled(LogLevel.Trace) && !string.IsNullOrWhiteSpace(url))
         {
             _logger.LogTrace(
                 "Created sitemap URL for action `{Action}` in controller `{Controller}`",
                 action.ActionName,
                 action.ControllerName);
+
         }
 
-        return new SitemapNode(url);
+        return !string.IsNullOrWhiteSpace(url) ? new SitemapNode(url) : null;
     }
 
     private HashSet<SitemapNode> GetControllerMethodsOptIn(Type controllerType, IEnumerable<ControllerActionDescriptor> actions)
@@ -114,7 +123,10 @@ private HashSet<SitemapNode> GetControllerMethodsOptIn(Type controllerType, IEnu
             if (includeFunction)
             {
                 var node = CreateNode(action);
-                nodes.Add(node);
+                if (node != null)
+                {
+                    nodes.Add(node);
+                }
             }
             else
             {
@@ -153,7 +165,10 @@ private HashSet<SitemapNode> GetControllerMethodsOptOut(Type controllerType, IEn
             if (!excludeFunction)
             {
                 var node = CreateNode(action);
-                nodes.Add(node);
+                if (node != null)
+                {
+                    nodes.Add(node);
+                }
             }
             else
             {

src/Sidio.Sitemap.AspNetCore/Sidio.Sitemap.AspNetCore.csproj

@@ -40,7 +40,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Sidio.Sitemap.Core" Version="2.3.0" />
+    <PackageReference Include="Sidio.Sitemap.Core" Version="2.5.0" />
   </ItemGroup>
 
 </Project>

src/Sidio.Sitemap.AspNetCore/SitemapExtensions.cs

@@ -0,0 +1,40 @@
+using System.Diagnostics;
+using Sidio.Sitemap.Core;
+
+namespace Sidio.Sitemap.AspNetCore;
+
+/// <summary>
+/// The Sitemap extensions.
+/// </summary>
+public static class SitemapExtensions
+{
+    /// <summary>
+    /// Adds a nullable URL to the sitemap.
+    /// </summary>
+    /// <param name="sitemap">The sitemap.</param>
+    /// <param name="url">The URL.</param>
+    /// <returns>Returns <c>true</c> when the url was added.</returns>
+    public static bool TryAdd(this Core.Sitemap sitemap, string? url)
+    {
+        if (string.IsNullOrWhiteSpace(url))
+        {
+            return false;
+        }
+
+        return sitemap.Add(new SitemapNode(url)) == 1;
+    }
+
+    /// <summary>
+    /// Adds a range of nullable URLs to the sitemap.
+    /// </summary>
+    /// <param name="sitemap">The sitemap.</param>
+    /// <param name="urls">The urls.</param>
+    /// <returns>Returns actual the number of nodes that were added.</returns>
+    public static int TryAdd(this Core.Sitemap sitemap, params string?[] urls)
+    {
+        var nonNullableUrls = urls.Where(x => !string.IsNullOrWhiteSpace(x))
+            .Select(x => new SitemapNode(x ?? throw new UnreachableException())).Cast<ISitemapNode>().ToArray();
+
+        return nonNullableUrls.Length > 0 ? sitemap.Add(nonNullableUrls) : 0;
+    }
+}

src/Sidio.Sitemap.AspNetCore/SitemapIndexExtensions.cs

@@ -0,0 +1,25 @@
+using Sidio.Sitemap.Core;
+
+namespace Sidio.Sitemap.AspNetCore;
+
+/// <summary>
+/// The Sitemap-index extensions.
+/// </summary>
+public static class SitemapIndexExtensions
+{
+    /// <summary>
+    /// Adds a nullable URL to the sitemap index.
+    /// </summary>
+    /// <param name="sitemapIndex">The sitemap index.</param>
+    /// <param name="url">The URL.</param>
+    /// <returns>Returns <c>true</c> when the url was added.</returns>
+    public static bool TryAdd(this SitemapIndex sitemapIndex, string? url)
+    {
+        if (string.IsNullOrWhiteSpace(url))
+        {
+            return false;
+        }
+
+        return sitemapIndex.Add(new SitemapIndexNode(url)) == 1;
+    }
+}